System and Method for Load Control

ABSTRACT

A system is described including a master power saving device configured for connection with a master load. The master power saving device is configured to determine when the master load is in an operating condition and a non-operating condition, and the master power saving device provides non-continuous power to the master load when the master load is in a non-operating condition. A slave power saving device is configured for connection with a slave load. The slave power saving device is configured to receive a signal from the master power saving device to turn off said slave load.

CROSS REFERENCE TO RELATED APPLICATION

This application is a Continuation and claims priority to U.S. patentapplication Ser. No. 12/494,155 filed on Jun. 29, 2009. This applicationis a Continuation in Part of U.S. patent application Ser. No.11/875,554, filed on Oct. 19, 2007, titled “SYSTEM AND METHOD FOR LOADCONTROL” which in turn claims priority to U.S. Provisional PatentApplication No. 60/980,987 filed on Oct. 18, 2007, titled “SYSTEM ANDMETHOD FOR LOAD CONTROL”, to Joseph W. Hodges et al., all of which areincorporated herein by reference.

TECHNICAL FIELD

The embodiments described herein are generally directed to control of anelectrical load.

BACKGROUND

Many electrical devices that utilize a plug-in power source (e.g.,household power connection) consume energy while switched off and not inuse. This is primarily due to a transformer or power supply that remainsconnected to the power source even during periods of inactivity. Onecommon method of powering these electrical devices includes a step-downtransformer with a regulator. Common examples of such devices includemobile phone chargers, VCRs, televisions, stereos, computers, andkitchen appliances.

The devices that remain powered waste energy through their transformersand/or power supplies that remain connected to the power source. Suchpower loss is commonly referred to as a phantom power load because thepower consumption does not serve a purpose. The electrical device orappliance is typically in a standby state or otherwise inactive whendrawing current and is not serving a useful function. In aggregate, alarge number of phantom loads contribute to a significant portion ofessentially wasted power.

One method of preventing a phantom load is to physically unplug anappliance from the electrical outlet when it is not in use. Thiscompletely disconnects the appliance from the power source andeliminates phantom loading. However, the user then must manually plug inthe load when load-use is desired and then unplug the load when use isno longer desired. Such ongoing plugging-in and unplugging may be a timeconsuming task as well as increase wear and tear on the electricaloutlet, plug, and wiring to the load.

Consequently, there is a need to reduce the amount of power consumptionfrom loads that are not in use to reduce energy waste. More generally,there is a need to selectively control a load based on the behavior ofthe load itself.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and inventive aspects will become more apparent uponreading the following detailed description, claims, and drawings, ofwhich the following is a brief description:

FIG. 1 is a block diagram of an energy saving device.

FIG. 2 is a schematic of an example of the energy saving device of FIG.1.

FIG. 3 is a state transition diagram for use with the energy savingdevice of FIG. 2.

FIG. 4 is a histogram classification graph for determining active andinactive states of the load of FIGS. 1 and 2.

FIG. 5 is a timing diagram for activation of the load of FIGS. 1 and 2.

FIG. 6 is a timing diagram for sensing and switching on the load ofFIGS. 1 and 2.

FIG. 7 is a current vs. time chart of load sensing when the load isactive.

FIG. 8 is a current vs. time chart of load sensing when the load isinactive.

FIG. 9 is an example of a wall outlet alternative energy saving device.

FIG. 10 is an example of a power strip including energy saving features.

FIG. 11 is an example of a state transition diagram for use with theenergy saving devices described herein.

FIG. 11A is an example of a timing diagram for an adaptive power savingssystem for use with the energy savings devices described herein.

FIG. 11B is an example of the power applied to the load in an energysaving mode and a full power mode.

FIG. 12 is an example of a state transition diagram for use with theenergy saving devices described herein.

FIG. 12A is an example of a clipped energy saving mode and a full powermode.

FIG. 13 is an example of power pulsing as applied to the example of FIG.11.

FIG. 14 is an example of cycle skipping that may be employed with theexample of FIG. 12.

FIG. 15 is an example of cycle clipping that may be employed during aclipped energy saving mode.

FIG. 15A is an example of a portion of an AC sine wave that has beenclipped.

FIG. 16 is an example of an energy savings system 1600 that communicateswith and controls other loads.

FIG. 17 is an example of a timing diagram for the energy saving deviceof FIG. 16.

FIG. 18 is an example of a human-in-area detection system for use withthe energy savings devices described herein.

FIG. 19A is a partial schematic of a power supply subsystem for use withthe power saving device.

FIG. 19B is a partial schematic of a load switch subsystem for use withthe power saving device.

FIG. 19C is a partial schematic of a logic subsystem for use with thepower saving device.

FIG. 19D is a partial schematic of a load current measurement subsystemfor use with the power saving device.

FIG. 20 is an example of a power measurement.

FIG. 21 is an example of an inrush waveform.

FIG. 22 is an example of a soft start waveform in comparison with aninrush waveform.

FIG. 23A is an example of a typical AC power supply waveform.

FIG. 23B is an example of gradual clipping of an AC power supplywaveform to achieve a soft start.

DETAILED DESCRIPTION

Referring now to the drawings, illustrative embodiments are shown indetail. Although the drawings represent the embodiments, the drawingsare not necessarily to scale and certain features may be exaggerated tobetter illustrate and explain novel aspects of an embodiment. Further,the embodiments described herein are not intended to be exhaustive orotherwise limit or restrict the claims to the precise form andconfiguration shown in the drawings and disclosed in the followingdetailed description.

This application is a Continuation in Part of U.S. patent applicationSer. No. 11/875,554, filed on Oct. 19, 2007, titled “SYSTEM AND METHODFOR LOAD CONTROL” which in turn claims priority to U.S. ProvisionalPatent Application No. 60/980,987 filed on Oct. 18, 2007, titled “SYSTEMAND METHOD FOR LOAD CONTROL”, to Joseph W. Hodges et al., all of whichare incorporated herein by reference.

An example of a device including a system and method of load control maybe an energy saving device that removes power to a load when the load isnot performing a useful function. In this way, phantom load power isreduced. When the load is performing a useful function, power issupplied normally until a phantom load is detected, at which time theload is disconnected from the power source. One example of such a loadis a household appliance that may not serve a useful purpose when a userdoes not require it to function, for example a television or a phonecharger. When a television is not turned on, it is still drawing aphantom load current to power the internal transformer and/or powersupply circuitry. However, the energy saving device discussed hereinwould interrupt the television's power input when the television is notin use. This interruption of the power input substantially eliminatesthe phantom load because the transformer or power supply electronics ofthe television are substantially un-powered and not drawing current.

An example of an energy saving device may include a measurement means, aswitch means, and a logic means. The measurement means may be configuredto detect current or power flowing to a load from a power source. Theswitch means may selectively connect and disconnect the load from thepower source. The logic means determines when to connect and disconnectthe load from the power source. In one example, the logic meansdetermines whether the load is “active” or “inactive” depending upon thecurrent or power consumption as read by the measurement means.

The logic means determines the state of the load by measuring thecurrent that the load consumes. To make a determination whether the loadis “active” or “inactive”, the logic means compares the current the loadis consuming to a threshold. The threshold may be predetermined value orit may be determined after the energy saving device is connected to theload (e.g., using a learning mode to define and/or characterize the loadpower usage). When the energy saving device uses a modifiable threshold,the value may be tuned for each load connected thereto. Such an adaptivesystem may be used where a large number of different loads could beconnected to a single type of energy saving device. For example,household appliances may consume a wide variety of power in the “active”and “inactive” states depending upon the particular appliance (e.g., atelevision, a radio, a phone charger) and/or circuit design usedtherein. The energy saving device may then adapt to the attached load.

Each load may have a preferred threshold that the logic means uses todetermine “active” and “inactive” states. This threshold may bedetermined by the energy saving device for each load connected to it andthus, an adaptable system may be used to allow for a variety of loads tobe switched by a single variety of energy saving devices. One method ofadaptive learning of the threshold includes recording current usage overa predetermined time (e.g., 24 hours). In the learning mode, the load ismaintained in a fully powered state so that the logic means can recordthe power usage. When the predetermined learning time has elapsed, athreshold can be set between the minimum and maximum currents recordedduring the learning mode. If no variation or minimal variation is notedin the recoded current measurement data, then a default threshold may beused.

Once the threshold is saved, the energy saving device logic meansmomentarily turns the load on to measure the current consumption. Thelogic means then compares the current consumption with the threshold. Ifthe current consumption is greater than the threshold, the logic meansdeems the load in the “active” state and maintains power to the load. Ifthe current consumption is less than the threshold, the logic meansdeems the load in the “inactive” state and power to the load is switchedoff. If the load is in the inactive state, the logic means occasionally(e.g., periodically) powers the load and repeats the above test todetermine the desired power state of the load as a function of theload's demand behavior.

By disconnecting the load from the power source when the load isinactive, the amount of phantom current is reduced. Energy conservationis realized when the load is disconnected from the power source duringtimes of inactivity. Power may be supplied to the load at predeterminedintervals (e.g., approximately 400 ms every 2 seconds) to check the loadstate. This may be called the “power duty cycle” which indicates howoften and for how long the load is powered for checking theactive/inactive state. The power duty cycle may be determined at thepoint of manufacture (e.g., stored in non-volatile memory) or it may beadaptable depending upon the load (and optionally a user input such as apushbutton).

In general, during “power cycling” the energy conservation devicemeasures current consumption at times when power is applied to the load.If the current consumed by the load is above the threshold, the load isdeemed in a “power on request” state. In this case, power cycling stopsand power is applied to the load continuously. This is the normal “on”operating state of the load, and power is not cycled. During the normaloperating state of the load, supplied current is monitored continuously.If the current is measured below the threshold, the load is determinedto have changed to the standby state. In this event, the power cyclingcondition resumes to conserve energy once again.

Generally discussed herein is a system that includes a means forreceiving a potential and selectively supplying said potential to aload. This receiving and supplying means may be configured as aswitching element that receives a voltage from a power source, such asfrom a standard power receptacle as is found in a house or otherstructures. The receiving and supplying means is also responsive to aload control signal to supply said potential to the load when the loadcontrol signal is present. The system also includes a means formeasuring a load demand where the load demand may include a current,voltage, power, or other measurement of load activity, power demand, orconsumption. The system may further include a means for controlling thereceiving and supplying means. The controlling means continuouslyproviding the load control signal when the load demand is greater than apredetermined threshold. The controlling means may also temporarilyprovide the load control signal to determine the load demand when theload demand is less than the predetermined threshold.

Another example as discussed herein is an electrical device thatincludes a switch responsive to a switching signal. The switch has ainput for receiving power and an output for connection to a load. Asensor may measure an electrical demand to the load which may include acurrent, voltage, power, or other measurement of load activity, powerdemand, or consumption. A controller selectively provides the switchingsignal. The controller provides the switching signal to power the loadwhen the electrical demand is greater than a predetermined threshold.The controller momentarily providing the switching signal to power theload after a delay to determine the electrical demand after the delay.

Also discussed herein is a method for controlling an electrical load.The method includes determining a load demand. The load demand mayinclude a current, voltage, power, or other measurement of loadactivity, power demand, or consumption. The method further includesprovisioning power to the load when the load demand is greater than afirst threshold. The method also includes removing power to the loadwhen the load demand is less than a second threshold.

FIG. 1 is an example block diagram of an energy saving device 100. Apair of Inputs 110 are configured for receiving a voltage from a powersource. A load 120 is connected to outputs that are selectively switchedto inputs 110 by a load switch 130. A controller 140 uses an activationsignal to load switch 130 to selectively supply power to load 120 frominputs 110. Controller 140 may base the activation signal on a number ofinputs, including a load sensor 150 and/or a user switch 170.Additionally, controller 140 may include a memory 142 that provides fornon-volatile storage of operating parameters of energy saving device100.

In an example, inputs 110 may be configured to interface with typicalpower infrastructures that may include standardized power distributionsystems. One example includes the United States' standard “householdpower” that operates at around 120 volts AC at 60 Hz. Alternatively,other voltages and frequencies may be used including typical 220 voltsat 50 Hz or 60 Hz. Indeed, energy saving device 100 should not belimited to household-type electrical connections, as it may also beemployed in a variety of circumstances including mobile loads,industrial, automotive, etc. For example, energy saving device 100 maybe applied to 120 volts AC at 60 Hz, 220 volts AC at 60 Hz, 220 volts ACat 50 Hz, 480 volts AC, 660 volts etc. Thus, energy saving device 100may be adapted for use with power infrastructures around the world (bothin voltage and in frequency), including but not limited to, household,industrial, mobile equipment, etc. Other examples may includeapplications such as aircraft, motor yachts, mobile homes, andautomobiles, etc., where power for non-essential electrical systems anddevices (e.g., infotainment or communications systems for passengers)may not require constant powering. Thus, in power-conscious applicationsenergy saving device 100 may generally reduce the steady-state load onthe power systems which may reduce operating costs, equipment costs,and/or maintenance costs.

As shown herein, a power supply 160 provides power for the operation ofcontroller 140 and the associated electronics such as load sensor 150and load switch 130. Power supply 160 may be configured so that energyis not wasted in the powering of controller 140. In another example,power supply 160 may include a battery that is rechargeable and/or userreplaceable. Such a battery configuration would not necessitate powerdrawn from inputs 110 to provide power to energy saving device 100.

Load sensor 150 may include a current measurement sensing topology thatmay include a high-side resistive differential amplifier (explainedbelow in detail with respect to FIG. 2). Such a system typicallyimplements a resistor in series between inputs 110 and load 120 suchthat the voltage drop across the series resistor is measured todetermine current flowing to load 120. The measured current to load 120may be sent to controller 140 at an analog to digital converter (ADC)input or an analog comparator input. Alternative implementations mayinclude a hall-effect sensor to measure current directly flowing frominputs 110 to load 120. In yet another example, a current measurementsystem may be integral with load switch 130 (such as a sense-FET).Moreover, power measurements or other means may be employed to determinewhether load 120 is in use.

In operation, controller 140 may occasionally power load 120 todetermine whether load 120 is to be activated continuously. If load 120demands a relatively large current (e.g., as detected by load sensor150), then load 120 is allowed to remain powered by continued activationof load switch 130. If load 120 demands a relatively small current, thenload 120 is deactivated by turning off load switch 130. In this way,controller 140 uses load sensor 150 to determine the active or inactivestatus of load 120. By not continuously powering load 120, a powersavings is realized through the momentary powering scheme when load 120is turned off and not demanding a relatively large current.

User switch 170 may be used to override the operation of controller 140to power the load based on a user request. For example, if the userbelieves that energy saving device 100 should power load 120, userswitch 170 may be activated to immediately power load 120. User switch170 may also be used by controller 140 as a training input. For example,if the user connects an arbitrary load to energy saving device 100 withdifferent characteristics than the previously trained load 120, then theuser may press user switch 170 to activate load 120 and signal tocontroller 140 that a training mode should be re-entered (explainedbelow in detail with respect to FIG. 3).

Memory 142 may be embodied as a Flash memory, an Electrically ErasableProgrammable Read-Only Memory (EEPROM) memory, or other non-volatilememory that retains information when un-powered. Typical informationstored in memory 142 may include statistical information related to theoperation of load 120 based on measurements from load sensor 150.Alternatively, memory 142 may include general parameter information thatdefines operational characteristics of controller 140.

In general, the block diagram shown herein is not to be interpreted asthe only example of how to configure energy saving device 100. Indeed,in some circumstances, controller 140 may be replaced by sequentiallogic circuitry, analog circuitry, or a combination of both. Moreover,as is known to those skilled in the art, measurement of load 120 usingload sensor 150 may include current, voltage, or power measurementsdepending upon the configuration. Thus, the current measurementtechnique for determining load consumption as discussed herein is notthe only means to measure load activity and load demand. Similarly, loadswitch 130 may be configured using variations of components such as afield-effect transistor (FET), Triode for Alternating Current (TRIAC),zero-crossing switches, or other switching means to control load 120.

FIG. 2 is a schematic of an example of an energy saving device 200. Apower supply block 210 is connected to a power input 260 and a commonterminal 262. A sensor block 220 measures the load current and a loadswitch block 230 generally controls the flow of power from power input260 to a load output 270. Load output 270 may be directly attached tothe power input to load 120 (shown in FIG. 1). While not necessary foroperation, user switch 250 provides for immediate activation of a load.Moreover, an infrared sensor block 240 may be used to determine theoperation of a user remote control, which requests immediate poweringthe load. This is used, for example, when a remote control is used toturn on a television. In this example, infrared sensor block 240 detectsuse of the remote and then the logic immediately turns on thetelevision.

Power supply block 210 includes a capacitive power supply topology forlow power operation. Power supply block 210 regulates a dual voltagesupply to about 12 volts and about 5 volts. A bridge rectifier BR1 isused to rectify the alternating current (AC) from power input 260 andcommon terminal 262. Zener diodes (D1, D2) and a capacitor network (C2,C3, C4) generally regulate the voltage. In addition to supplying powerto energy saving device 200, power supply block 210 also provides avoltage reference (Vref) for use with the current detection circuitry.

Sensor block 220 includes a series resistor R6 that is configured as alow-value resistor with a high power rating. For example, seriesresistor R6 may be a one-ohm resistor rated for 200 watts of power. Adifferential amplifier configuration is used that includes U2A, U2B, andVref (from power supply block 210) to measure the current flowingthrough series resistor R6 to a load connected to load output 270. Aload signal 280 is provided to controller U1 that contains control logicfor operating load switch block 230. Controller U1 may be configured toreceive load signal 280 at an analog to digital converter (ADC) input toconvert the analog signal to a numeric value. In general, load signal280 indicates to controller U1 the amount of current or power beingconsumed/demanded by the electrical load connected to load output 270.The load consumed by the circuitry described in the schematic of FIG. 2does not draw power through sense resistor R6. Thus, any power consumedby the circuitry shown herein is not included in the load demand valueindicated by load signal 280.

Although shown herein as a single-range sensing scheme with a singleoutput of load signal 280, sensor block 220 may also include multipleranges of sensed current. For example, a second load signal (not shown)may be measured by controller U1 provided by a signal at the output ofamplifier U2A. Thus, controller U1 would then be able to detect currentover two ranges provided by the outputs of both U2A and U2B, which wouldbe connected to separate ADC inputs of U1. Alternative examples may alsoinclude a low-side measurement scheme or a Hall-effect load measurementscheme.

Controller U1, in an example, may be configured as a micro-controllercapable of performing the actions detailed in FIG. 3. Examples ofmicro-controllers known to those skilled in the art may include, forexample, PIC (TM) micro-controllers from Microchip (TM), or AVR (TM)micro-controllers from Atmel (TM). For compact designs, the exampleshown herein includes a relatively small device that may have eightpins. However, energy saving device 200 may include other features notdetailed herein, including radio frequency reception for furtherintelligent control of a load. Moreover, micro-controller U1 may controlmore than one load based on a single sensor block 220, or more than onesensor block 220. Thus, controller U1 may be scaled up or down incapabilities depending upon the measurement and control requirements fora particular application.

Load switch block 230 includes a FET driver circuit for controllingpower to a load connected to load output 270. The load (as shown in FIG.1 as load 120) is electrically connected to load output 270 and commonterminal 262. A load control signal 286 is provided by controller U1 tocontrol load switch block 230. Load switch block 230 activates (powers)or deactivates (disconnects) a load (e.g., a device or appliance)connected to load output 270. Load switch block 230 generally includes acharge pump, including U3A and U3B, that drives a bridge rectifier BR2that in turn drives FETs Q4 and Q5. A Metal Oxide Varistor (MOV) isincluded to protect the relatively sensitive FETs Q4 and Q5 when theload connected at load output 270 is switched off. The MOV may alsoperform a secondary function as a surge suppressor for potentiallydamaging signals present at power input 260.

An additional feature may include a user output signal 288 fromcontroller U1 that switches a LED D7. Output signal 288 may be used toindicate an operating status (e.g., load on or off) of energy savingdevice 200 to the user. Alternatively, output signal 288 may indicatethat energy saving device 200 is in a learning mode (discussed below indetail with respect to FIG. 3) or whether an abnormal load conditionexists that may require turning off the load to preserve theelectronics.

Other examples of inputs that may trigger controller 140 to turn on load120 (similar to infrared sensor block 240 and user switch 250) mayinclude a general radio frequency input, a network input (such as a LANor WiFi), digital information transmitted over the power line at powerinput 260, and/or signals designed for intelligent control of electricaldevices, etc.

FIG. 3 is a state transition diagram 300 for use with energy savingdevice 200 of FIG. 2. Initial entry point 310 leads to an activate loadtransition 312. A typical event for energy saving device 100 to enterinitial entry point 310 is when the unit is plugged into a power source.A power up mode 314 is then entered where the load is powered for apredetermined delay time. Typically, a timer/counter is used inconjunction with controller 140 (see FIG. 1). When the delay haselapsed, a power up timer expired transition 316 transfers to ateach/learn state 320.

Initial entry to teach/learn state 320 transitions to a learn state 322where controller 140 measures the current (electrical demand) used bythe load over a predetermined amount of time. Here, controller 140determines the behavior of the load over a number of on and off cycles.By examining the load behavior, the controller may determine when theload is in use by the pattern of “load active” current consumption and“load inactive” current consumption (explained in detail below withrespect to FIG. 4).

Controller 140 remains in learn state 322 until a learn timer expiredtransition 324 transfers control to a set threshold state 326.Controller 140 then calculates an appropriate threshold to distinguishthe load “active” and “inactive” states. When the threshold has beendetermined, a threshold stored/activate load transition 288 transferscontrol to a sleep check load status state 330. Thresholdstored/activate load transition 288 generally indicates that thethreshold has been stored in memory (which may include a non-volatilememory such as memory 142 of FIG. 1).

Alternatively, the threshold may be a hard-coded value placed innon-volatile memory during manufacturing. Another alternative mayprovide a table of hard-coded threshold values. If the threshold doesnot suit the particular load connected, the user may push user switch170 (shown in FIG. 1) to indicate to the controller that the currentthreshold is not functioning as desired. The controller may then selectanother threshold value from the table using, for example, a bisectionalgorithm to locate the appropriate threshold value for the load toreduce required user interaction.

Sleep check load status state 330 has an initial entry point 332 whichimmediately transfers control to a pulse activate load state 334. Pulseactivate load state 334 activates the load and waits for a predeterminedtime for the current signal to stabilize. A current stabilizedtransition 336 transfers control to a current compare state 338 wherethe current measured through the load is compared to the thresholddetermined in set threshold state 326. If the current measured throughthe load is greater than the threshold, a current high activate loadtransition 346 transfers control to an activate load state 350.

Alternatively, if the current measured through the load is less than thethreshold, a current low deactivate load transition 340 transferscontrol to a sleep deactivate load state 342 where the load isdeactivated. In sleep deactivate load state 342, a timer may bemonitored to determine when a predetermined sleep time has elapsed. Whenthe predetermined sleep time has elapsed, a sleep timer expired activateload transition 344 transfers control back to pulse activate load state334. As can be determined from sleep check load status state 330, thecontroller may repeat a cycle where the load is measured for significantuse or insignificant use. When a current is measured that is greaterthan the threshold, the load is turned on. Similarly, when a current ismeasured that is less than the threshold, the load is turned off. Alsonoted is that controller 140 may include hysteresis for the thresholdvalue in the on-to-off and off-to-on transitions to avoid oscillationand/or undesirable activation and deactivation.

In activate load state 350, the controller monitors the current for atransition to a low current consumption state of the load. When acurrent is measured less than the threshold determined in set thresholdstate 326, then current is turned off to the load. A current lowtransition 352 is then triggered and control proceeds to entry point 332and pulse activate load state 334.

FIG. 4 is an example of a histogram classification graph 400 fordetermining active and inactive states of load 120 of FIGS. 1 and 2.During learn state 322 of teach/learn state 320 (described in detailwith respect to FIG. 3), the controller monitors the usage of the loadto collect information. As shown in the chart, current magnitude ismeasured over time to develop two distinct regions. On the right handside of the chart, an active state 420 is indicated by a large number ofsamples. Similarly, a large number of samples on the left hand side ofthe chart indicate an inactive state 410. When the controller hascollected enough information, or a timer has expired, then themicrocontroller transfers control to set threshold state 326.

A threshold 430 may be determined in a number of manners. However, manyloads exhibit dramatic differences in load demand behavior when inactiveand active. Thus, for many applications the simple classificationproblem of the active and inactive states is solved by determining theaverage difference between clusters of measurements. These clusters ofmeasured current, in this example, are shown by the two distinctmeasured current regions for inactive state 410 and active state 420.Although not shown, threshold 430 may include hysteresis that wouldsubstantially prevent undesirable switching of the load.

FIG. 5 is a timing diagram 500 for activation of load 120 of FIGS. 1 and2. Timing diagram 500 generally refers to the sequence of applying powerand removing power during sleep check load status state 330 of FIG. 3.At an activation time 510, load 120 (of FIG. 1) is provided power basedon sleep timer expired activate load transition 344 to pulse activateload state 334 of FIG. 3.

A load activation time 520 allows controller 140 to determine whetherload 120 is desired to be fully powered. In general, load activationtime 520 includes the logic processes of current stabilized transition336 and current compare state 338 of FIG. 3. A decision time 530indicates that controller 140 is testing the current measured by loadsensor 150 (of FIG. 1) against threshold 430 (of FIG. 4). At decisiontime 530, load 120 is deactivated because the current measured is lessthan threshold 430. Load 120 is then deactivated during an inactive time540. Further repetitions of activation time 510 and inactive time 540demonstrate that load 120 is continuously demanding current less thanthreshold 430. Although timing diagram 500 shows a periodic interval foractivation time 510 and inactive time 540, it is also possible toconfigure each timing sequence with a non-periodic time such that someactivations and/or deactivations are not equally spaced in time. Forexample, if the current measured is close to threshold 430, controller140 may reduce the time between checking for activation and deactivationin an attempt to more closely monitor load demand.

FIG. 6 is a timing diagram 600 for sensing and switching load 120 ofFIGS. 1 and 2. In this example, activation time 510 powers load 120 fora load activation time 520. Then, at decision time 530 it is determinedthat load 120 is consuming a current greater than threshold 430. Afterthe determination (corresponding to current high activate loadtransition 346 of FIG. 3), load 120 remains active for a load activetime 610 that includes activate load state 350. Load 120 will remainactive until a current low transition 352 is triggered by the current toload 120 dropping below threshold 430 (not shown in FIG. 6).

FIG. 7 is a current vs. time chart 800 of load sensing when load 120 isactive. In this example, the current as measured by load sensor 150(shown in FIG. 1) is shown in an analog chart form. At inactive time 540(shown in FIG. 5) substantially no current is flowing to load 120.However, at activation time 510, a ramp up of current 812 indicates thatload 120 is demanding current flow. During a stabilization period 820,the current flow may oscillate or otherwise behave unpredictably due tothe unknown nature of load 120. It is during stabilization period 820that load 120 receives full power to initialize the systems (if logicbased) or otherwise transition to a fully powered state. At astabilization end time 830, a sampling window 840 is used to sample theload current. At this time, one or more samples are taken from loadsensor 150 to determine whether load 120 is drawing more current thanthreshold 430. As shown at decision time 530, load 120 remains activebecause the current to load 120 is greater than threshold 430.Therefore, load 120 remains active for load active time 610.

FIG. 8 is a current vs. time chart 880 of load sensing when load 120 isinactive. Here, the current as measured by load sensor 150 (shown inFIG. 1) is shown in an analog chart form with a slightly higher zoomfactor when compared with FIG. 7 (although the figures are not toscale). At inactive time 540 (shown in FIG. 5), substantially no currentis flowing to load 120. At activation time 510, a ramp up of current 812indicates that load 120 is demanding current flow. During astabilization period 820, the current flow oscillates but does notoscillate to the extent as shown in FIG. 7. At a stabilization end time830, sampling window 840 is used to sample the load current. At decisiontime 530, load 120 is deactivated because the current demand is lessthan threshold 430. Load 120 will remain inactive for inactive time 540until the next activation time 510 or a user activation.

FIG. 9 is an example of a wall outlet alternative energy saving device900. The example here shows a stylized packaging alternative for theenergy saving device 100 of FIG. 1. In use, a user may plug device 900into a standard dual outlet where power pins 920, 930 connect with thereceptacle and hold device 900 in place. Device 900 may be encased in ahousing 910 and includes two receptacles 922, 932 for the user to plugin loads. Here, energy saving device 100 is employed as a userinstallable device for retro-fitting existing receptacles. In thisexample, power pins 920 map to inputs 110 (see FIG. 1) and receptacle932 maps to where load 120 (see FIG. 1) is plugged in.

FIG. 10 is an example of a power strip 1000 that includes an alternativeenergy saving device. A configuration similar to a “power strip” 1010 isshown having a power source plug 1020 as an input. Outputs include amaster outlet 1030 and multi-slave outlets 1040, 1042, 1044 controlledby an energy saving device that monitors master outlet 1030. However,energy saving device 1000 does not simply switch slaves 1040, 1042, 1044based on the power consumption of master 1030. Rather, energy savingdevice 1000 switches all of master 1030 and slaves 1040, 1042, 1044based on the power consumption of master 1030. The user has a manualinput (e.g., user switch 170) to override the operation of energy savingdevice 1000 to manually switch the outlets on or off.

Moreover, as discussed herein, the energy saving device may also bebuilt into a product for saving power. In an example, the energy savingdevice may be designed into the circuitry of a television to reducepower consumption. In another example, the energy saving device may bedesigned into a phone charger. In yet another example, the energy savingdevice may be designed into a standard transformer for use generallywith electronics and electrical devices. Moreover, the systems andmethods described herein may be used to provision power to sub-systemswithin larger designs and need not be located at the main power input.

By employing the examples of energy saving devices as described herein,energy loss from phantom loads may be reduced significantly. Forexample, a television that includes a cathode ray tube (CRT) with atransformer-based power supply may consume around 120 Watts when active.When inactive (e.g., in a standby mode) the idle power consumption maybe around 8 Watts of phantom load. When using the energy saving devicesas described herein, power savings from phantom loads may be around 66%which is a direct function of the active duty cycle percentage asdescribed above with respect to FIGS. 3 and 4. Thus, the power consumedby the television when an energy saving device is employed may be around2.6 Watts at idle. The difference from an always-connected idlecondition (8 Watts) is about 5.4 Watts of saved power. Other devices mayinclude, for example a laptop computer power supply which at standbyconsumes about 3 Watts of phantom load. Another example is a desktopcomputer that consumes about 8 Watts at idle.

Examples of the threshold as discussed herein to determine the load is“active” or “inactive” state are discussed in detail above and inparticular with FIGS. 3, 4, 7, and 8. In the example of a CRTtelevision, the inactive state demands about 8 Watts and the activestate demands about 120 Watts. The threshold may then be safely setanywhere between 8 Watts and 120 Watts. However, a margin of error maybe factored in to allow the threshold to be used with a multitude of CRTtelevisions or to account for manufacturing variations that could shiftthe inactive and active power demand. Thus, a safe threshold value maybe set at 64 Watts, which is the midpoint between the active andinactive power demand values. In another example, a laptop computerpower supply demands around 3 Watts while inactive and about 26 Wattswhen active. Thus, a safe threshold value may be set at 14.5 Watts. Inanother example, a desktop computer power supply demands around 8 Wattswhile inactive and about 120 Watts when active. Thus, a safe thresholdvalue may be set at 64 Watts. Of note is that while the power demandvalues are discussed in watts, as well as the threshold in the instantcase, the actual threshold value used depends upon the methodology usedto determine the load demand which may include current measurement,power measurement, or voltage measurement. One of ordinary skill in theart will recognize that the threshold value may be adapted to theparticular load demand measurement employed.

It is noted that the above examples are not indicative of any particularload and should not be used in any way to limit this disclosure. Indeed,televisions, laptop computer power supplies, and desktop computers, areonly some examples of load types that may be employed using the loadcontrol method including an energy saving device. Moreover, each loaddiscussed herein is used as an example of how to employ an energy savingdevice. The loads may have wide ranges of active demands and inactivedemands based on their technology, manufacture, intended use, and otherconditions. Thus, the loads, and in particular, threshold valuesdiscussed do not translate to limiting values and are only exemplary.

FIG. 11 is an example of a state transition diagram 1100 for use withthe energy saving devices described herein. From a reset state thesystem enters a learn state 1110 where the power saving device adapts toan arbitrary load. This adaptation may include applying power to a loadand determining the “on” and “off” currents as well as determining thethresholds for the power saving device to use when determining the powerstate of “on” and “off” for the load. Learn state 1110 is described indetail below with respect to FIG. 11A. After learn state 1110 iscomplete, control proceeds to a measure current state 1120.

In measure current state 1120, power is applied to the load and thepower saving device determines whether a load demands power equal to ormore than the “on” threshold determined in learn state 1110, or whetherthe load demands power less than or equal to the “off” thresholddetermined in learn state 1110. To provide hysteresis, if the initialpower demanded by the load when entering measure current state 1120meets the “on” threshold, then the power is determined to be “high” andcontrol remains at measure current state 1120 with full power applied tothe load. If the power demanded by the load meets the “off” threshold,then the power is determined to be “low” and control proceeds to powerdown load state 1130.

In power down load state 1130, power is turned off to the load and apower saving is achieved. Control then proceeds to off wait state 1140.

In off wait state 1140, a time delay is measured for a predeterminedtime with the power turned off to the load. When the predetermined timeelapses, control proceeds to apply power to load state 1150. Note thatthe predetermined time may be adjustable for various power saving modeschemes. For example, as discussed below with respect to FIG. 18, thedelay may be adjustable to predetermined times to allow for increasedpower savings, or alternatively, increased response time of the loadturn-on.

In apply power to load state 1150, full power is applied to the load.Control then proceeds to an on wait state 1160.

In on wait state 1160, a time delay is measured for a predetermined timewith the power turned on to the load. This predetermined time allows forthe load power to stabilize after initial turn on so that measurementsmay proceed later in the process to determine the operating power of theload, rather than the inrush load on initial turn on. When thepredetermined time elapses, control proceeds to measure current mode1120 and the process repeats.

FIG. 11A is an example of a timing diagram 1170 for an adaptive powersavings system for use with the energy savings devices described herein.A first timing diagram 1172 shows the power to the load as “on” or“off”. A second timing diagram 1180 shows the status of the load powerbutton as triggered by a user. A third timing diagram 1190 shows theload current demand.

To determine the whether a load is turned “on”, (e.g., for a televisionor other appliance) the minimum length of time with full power appliedto the load for testing the power demand thresholds may be a fixed time,or it may be adjustable (e.g., as discussed above with respect tomeasure current state 1120 of FIG. 11). This minimum “on” time allowsthe load to turn on and the power consumption to stabilize. If, forexample, the “on” time is too short, the load may not have enough timeto achieve a fully “on” state and the power demand measurement may beinaccurate, or may be premature, resulting in an incorrect determinationof the load's power state. To allow for arbitrary loads being connectedto the power saving device, the power “on” time may be adaptive forvarious loads in a learning mode.

In an example, the user may turn the load “on” 1182 by holding theload's power button or remote button and hold the power “on” during atesting period 1184. After testing period 1184 is complete, the user mayrelease the power button 1186. In coordination with learn mode 1110 ofFIG. 11, the learn mode may be triggered by the power saving device, forexample, by a user button or when the power saving device is initiallyconnected to the power source and the load connected to the power savingdevice. When learn mode 1110 is active, the power saving device maysweep the “on” time from a short time to a longer time to determine thethreshold at which the load demands power above the “on” threshold. Forexample, the initial “on” time 1173 may be a short on time (e.g., 50 ms)and if the load does not demand power above the “on” threshold then thepower saving device may increase the “on” time 1175, 1177, 1179 untilthe load crosses the “on” power demand threshold 1194. Between the fullpower “on” times, an “off” time 1174, 1176, 1178 is provided so that theload has an opportunity to power “off” to avoid a false positiveindication of the load status and/or load demand. Note that althoughFIG. 11A as discussed herein provides three examples of pulse widths forthe “on” time (e.g., “on” times 1175, 1177, 1179) the adjustable processmay be provided with only two pulse widths, or may continue with aninfinite number of increasing duration pulse widths.

As shown in timing diagram 1170, the load is determined to be “off”during a test period 1192, and then when full power is applied to theload for a long enough time 1179, the load demands power above theon/off threshold 1193. At this time, learn mode 1110 may determine thatthe load needs a minimum full power on time described by time period1179 before a determination can be made as to the load status of on oroff. In this way, the power saving device may optimize the “on” time fortesting load demand to further reduce power consumption when the load is“off”.

The variable times for each “on” time 1173, 1175, 1177, 1179 may berelated back to FIGS. 7 and 8 as the time from activation time 510 tostabilization end time 830 and/or decision time 530 (see FIGS. 7 and 8).Alternatively, the Each “on” time 1173, 1175, 1177, 1179 may have anincreasing time providing for more time the load during stabilizationperiod 820 and prior to sampling window 840. Moreover, when used inconjunction with a soft start feature (disclosed below with respect toFIG. 23B) the inrush may be reduced which may substantially reducefalse-positive determinations that a load is “on”.

FIG. 11B is an example of the power applied to the load in an energysaving mode 1195 (e.g., non-continuous power when the load is in anon-operating condition) and a full power mode 1198 (e.g., continuouspower when the load is in an operating condition). When a load is “off”,the power saving device may turn the load “on” 1196 to test the loadpower demand, such as is performed in measure current state 1120. If theload power demand is determined to be in the “off” state, power isturned off for a predetermined time 1197 to save power. Alternatively,if the load power demand is determined to be in the “on” state, fullpower is turned on 1198 to the load allowing normal use of the load. Ifload demand reduces to below the “off” threshold, the power savingdevice reverts back to energy saving mode 1195.

FIG. 12 is an example of a state transition diagram 1200 for use withthe energy saving devices described herein. As discussed above withrespect to FIGS. 11 and 11A, a learn state 1110 may be included to allowfor optimization and/or adjustment of the load on/off times to determinethe load status, and a measure current mode 1120 to allow for thedetermination of load power demand and load status. Diagram 1200 showsan alternative power saving mode that allows for cycle skipping and/orcycle clipping. In measure current state 1120, if the load power demandmeets the “off” criteria, control proceeds to the cycle skip/clip state1210. In cycle skip/clip state 1210, the power to the load may bemodified to include cycle skipping and/or cycle clipping to provideenergy savings. For example, cycle skipping allows for a single cycle of“on” and a predetermined number of cycles of “off” to be sent to theload. This power saving strategy may allow some power to be applied tokeep the load “alive” during the off periods to preserve, for example,volatile memory in the load. Alternatively, cycle clipping may beemployed to send power to the load, but certain portions of the cyclesmay be clipped to conserve power. After cycle skip/clip state 1210 isinitiated, control transfers to a wait state 1220. When a predeterminedwait time has elapsed, the control proceeds to measure current state1120 where the load may be tested for power demand.

FIG. 12A is an example of a clipped energy saving mode 1210 and a fullpower mode 1120. When clipping is employed for power saving, only aportion of the power is provided to the load. As shown in FIG. 15, cycleclipping may be employed during clipped energy saving mode 1210. Theclipping may provide only a portion of an AC power signal to the load toconserve power. For example, FIG. 15A shows a portion of an AC sine wavethat has been clipped. An on portion 1510 is provided where power flowsto the load. An off portion 1520 is where the AC cycle has been clipped.An ideal AC signal would have the full partial cycle 1530. However, theclipping turns power off at clipping point 1540.

FIG. 13 is an example of power pulsing as applied to the example of FIG.11. Power is applied 1310 for a predetermined time (e.g., correspondingto full power mode 1120) and power is turned off for a predeterminedtime (e.g., corresponding to power down load state 1130). Thepredetermined on and off times may be adjusted using various techniquesas described herein, including response to a human-in-area detectionsystem (see FIG. 18).

FIG. 14 is an example of cycle skipping, that may be employed with theexample of FIG. 12. When cycle skipping (e.g., during cycle skip/clipstate 1210), a full cycle may be provided to the load followed by an offperiod. In this way, the load may be provided with some power during theenergy saving period rather than having power fully off.

FIG. 16 is an example of an energy savings system 1600 that communicateswith and controls other loads. A master load 1630 (e.g., such as atelevision) may be controlled from a master energy saving device 1620.Master energy saving device 1620 may communicate (e.g., digital and/oranalog communication) with slave power savings devices 1622, 1624, 1626using the power lines (e.g., power wiring). Slave power savings devices1622, 1624, 1626 may control slave loads such as a receiver 1632, a gamestation 1634, and a DVD player 1636, respectively. The slave loads 1632,1634, 1636 may be configured with the slave power saving devices suchthat when the master load 1630 is not in use, the power is turned off toslave loads 1632, 1634, 1636. This system configuration allows masterpower saving device 1620 to determine the on/off status of master load1630 and control slave loads 1632, 1634, 1636 to a full off status whenmaster load 1630 is determined to be off, and a full on status whenmaster load 1630 is determined to be on. In this way, additional powersavings may be achieved for slave loads 1632, 1634, 1636 when masterload 1630 is off.

Communication from master energy saving device 1620 and slave powersavings devices 1622, 1624, 1626 may be through the power wiring, suchas is described by the X10 standard for home automation, or otherprotocols (e.g., power line communication). Alternatively, thecommunication may be wireless (e.g., Bluetooth or 802.11-typecommunications). Moreover, to facilitate communications, master energysaving device 1620 may be keyed to slave power savings devices 1622,1624, 1626 using a code that may be programmed by a user, orpre-programmed. Such a keying system allows for multiple masters andslaves to operate independently using the same communication medium(e.g., wiring or wireless).

FIG. 17 is an example of a timing diagram 1700 for the energy savingdevice of FIG. 16. During a power saving mode 1710 when master load 1630is determined to be off, all slaves 1632, 1634, 1636 are turned off. Formaster load 1630, master power saving device 1620 may periodicallydetermine the power status to determine whether the load is on or off.When master load 1630 is turned on 1730, master power saving device 1620turns the master load to full power 1720 and sends a signal to slavepower savings devices 1622, 1624, 1626 to turn all slaves on 1742 (e.g.,see slaves 1632, 1634, 1636 of FIG. 16). When master load 1630 is turnedoff 1732, master power saving device 1620 reverts to power saving mode1710 and sends a signal to slave power savings devices 1622, 1624, 1626to turn all slaves off 1740 (e.g., see slaves 1632, 1634, 1636 of FIG.16).

FIG. 18 is an example of a human-in-area detection system 1800 for usewith the energy savings devices described herein. In an example, asensor or detector 1810 may be configured for use with power savingdevices 1812, 1814, 1816. Sensor 1810 may be configured as a motionsensor, a thermal sensor, a sound sensor, or other type of sensor todetect persons, for example without limitation. Sensor 1810 may detect aperson 1802 within a predetermined proximity and communicate thepresence of the person 1820 to power saving devices 1812, 1814, 1816 asa “human-in-area” (“HIA”) signal. Alternatively, when person 1802 is notdetected or in range of sensor 1810, a “no-human-in-area” (“NHIA”)signal may communicate to power saving devices 1812, 1814, 1816.

Power saving devices 1812, 1814, 1816 may then use the HIA or NHIAsignals to alter their power saving strategies to provide for increasedpower savings when the NHIA signal is present, or to increase responsetime when the HIA signal is present. For example, power saving device1812 may be connected to a television load 1820. When the HIA signal ispresent, a decreased response time strategy 1840 may be employed wherethe duration between testing the load status is reduced. Alternatively,when the NHIA signal is present, an increased power saving strategy 1842may be employed that increases the duration between testing the loadstatus. In and example, the period of the pulses of power for theincreased power saving strategy 1842 (e.g., a second power savingstrategy) is longer than the period of the pulses of power for theincreased response time strategy 1840.

In another example, a personal computer 1822 may be connected to a powersaving device 1814. In this example, when the HIA signal is present, thepower saving mode may be unchanged from a normal power saving mode.However, when the NHIA signal is present, the load may be switchedcompletely off 1852 to achieve greater power savings.

Other loads 1824 may be controlled by power saving device 1816 that mayor may not change power saving strategies upon the present of the HIA orNHIA signals.

When discussing the HIA and NHIA power saving strategies as it relatesto the power saving devices as discuss herein, sensor 1810 does notdirectly control the on/off status of the load. However, where the powersaving devices are configured to use the HIA and NHIA signals, they mayalter their power strategies.

Communication from sensor 1810 and power saving devices 1812, 1814, 1816may use wired, including power wiring, or wireless communications. Also,note that while motion sensor 1810 is shown as a separate unit in FIG.18, it may also be integrated with a power saving device.

FIG. 19A is a partial schematic of a power supply subsystem for use withthe power saving device. In general, the power supply subsystem convertsthe AC mains power to 5V DC used for power the load switch subsystem(see FIG. 19B), the logic subsystem (see FIG. 19C), load currentmeasurement subsystems (see FIG. 19D), and user input/output.

The power supply subsystem is generally divided into an AC and DCsection that is divided by diode D2. The AC section includes inrushprotection resistors R24, R25 to prevent excessive current spikes.Capacitor C6 functions as an isolation capacitor that couples energyfrom AC mains into regulator DC section. Diodes D5, D6 provide overvoltage protection. Diodes D2, D3 are half wave rectifiers for AC to DCconversion.

In the DC section, capacitor C8 functions as a preregulator holdingcapacitor to smooth AC signal into DC. Capacitor C1 functions as a highfrequency filter capacitor. Diode D11 (a Zener diode) functions as apreregulator to prevent over voltage to remaining circuit elements.Resistors R7, R10 function as a Zener shunt regulator resistor which incombination with diode D4 (a zener diode) forms basis of 5V DCregulator. Capacitor C7 functions as a power supply low frequencysmoothing capacitor. Capacitor C2 functions as a high frequency filtercapacitor. Resistors R14, R15 function as a voltage divider (generally2:1) to supply a ½ Vcc reference voltage to the load current measurementsubsystem.

FIG. 19B is a partial schematic of a load switch subsystem for use withthe power saving device. The load switch subsystem functions to apply orcut power to the load under instruction from the logic subsystem.

Optoisolator U2 and resistor R3 permit AC power to be applied/cut to theload by a low voltage DC microcontroller (see U1 of FIG. 19C). ResistorsR19, capacitor C10, and resistors R2, R6 function as a triac biasingcircuit, capable of handling reactive loads. Resistor R18 functions as azero cross detector resistor used to inform the logic subsystem when ACsignal is generally at zero volts. The zero cross detector is generallyused to apply/cut power synchronous to the AC mains voltage signal.Resistor R20 and capacitor C9 function as a TRIAC snubber circuit whichprevents inadvertent turn-on of TRIAC with reactive loads. TRIAC Q1 isused as a switching element to apply/cut power to load. Fuse F1functions as a safety fuse to prevent undesirable failure modes in caseof circuit failure or user connecting an excessive current demand loadbeyond the rated use. MOV RV1 (a Metal Oxide Varistor) functions foroutput protection. Connectors J1, J2 are male and female AC connections.

FIG. 19C is a partial schematic of a logic subsystem for use with thepower saving device. The logic subsystem performs command and control ofthe power saving device and controls energy savings functions byinstructing modulation of power to load based on load state and loadon/off demand as sensed by the load current measurement block (shown inFIG. 19D).

Microcontroller U1 is a microcontroller with internal ND (analog todigital converter) and EEProm (non-volatile storage) that executessoftware capable of controlling the load as discussed herein based onvarious scenarios that include evaluation of load current demand.Crystal Y1 and capacitors C11, C12 function as an oscillator for themicrocontroller U1. Diode D9, capacitor C5 and resistors R13, R4function as a reset circuit for microcontroller U1. Resistors R21, 22and diode D10 function as an AC mains voltage monitor used for datacollection device to calculate true power. Switch U4 (shown here as aHall Effect sensor) and resistor R27 function to read a user command forentering learning modes and other user-input related features. Switch S1and resistor R28 are an alternative user input configuration having astandard push button switch. Resistor R12 and diode D8 function as astatus LED to indicate system status to user. Capacitors C3, 13 functionas high frequency bypass capacitors. Jack J4 and resistor R17 providefor flash programming of microcontroller U1.

FIG. 19D is a partial schematic of a load current measurement subsystemfor use with the power saving device. The load current measurementsubsystem measures load current demands and present it to the logicsubsystem in a usable form (e.g., 0-5V for analog to digitalconversion). In general, the topology of the load current measurementsubsystem includes a ground reference resistive 2 stage differentialamplifier.

Operational amplifier U3 is a low current, low offset voltage rail torail CMOS OP amp. Resistor R1 is a sense resistor to convert loadcurrent into a low voltage (for later amplification). Resistors R5, R8,R9, R11, R16, and R26 are resistors chosen to provide a two stagedifferential amplifier with 82 counts per amp for stage 1 and 820 countsper amp for stage 2 with R1 as the sense resistor. Paired diodes D7function as microcontroller input protection diodes. Capacitor C4functions as a high frequency bypass capacitor.

FIG. 20 is an example of a power measurement including time and ADCcounts as references. For reference a standard AC mains signal 2010 isoverlaid for context. The ADC counts correspond to a current measurementgenerally provided by the load current measurement subsystem shown inFIG. 19D and as converted by the ADC of microcontroller U1 (shown inFIG. 19C). As shown the lower the ADC count, the higher the powerconsumption. At the peak of the sine wave 2020, many loads exhibit aspike in power consumption 2030 (shown as the downwardly extending powerspike). This may be due to switching regulators at the load that pullpower in short bursts to increase efficiency. An example of a burstcurrent is about 5A which corresponds to about 550W, where the averagepower of the load shown may be about 67W. This short burst of powerconsumption at the peak of the AC sine wave 2020 may be caused by theinductive nature of the power supply transformer and capacitorreactances in the load. However, each load may perform differently, andmay not include a power spike 2030 at all depending on the loadconfiguration.

FIGS. 21-23B discuss a soft start system that may reduce wear-and-tearon electrical components in the load that may include derating of thecomponents. In general, the soft start system reduces the inrush currentand voltage to avoid derating of components. For example, many commoncapacitors derate over their life based on current spikes. Forcapacitors, such as electrolytic capacitors in a load power supply, theinrush current may momentarily present as a short-circuit condition tothe component which stresses the component. Alternatively, if thecurrent spikes are reduced to a smoother voltage profile they may derateslower and last longer.

FIG. 21 is an example of an inrush waveform 2100. When power is appliedto the load an inrush 2110 typically occurs (e.g., see also inrushcurrent 812 of FIG. 8) where the load demand greater power than whenoperating in a normal stable operating condition. This inrush at theinitial connection of power may draw excessive power (thus wastingpower) and may derate the electrical components of the load. Moreover,by controlling high inrush demands via the soft start feature, energymay be saved.

FIG. 22 is an example of a soft start waveform in comparison with aninrush waveform. Soft start waveform 2210 shows a gradual application ofpower to the load that reduces the inrush spike (shown in FIG. 22 as adashed line and shown in FIG. 21 as inrush 2110). The soft startwaveform 2210 shows a gradual application of power to the load (shown inFIG. 23B) that generally reduces the over-voltage and/or over-currentconditions generally associated with application of power to certainloads. Because the maximum power applied using soft start waveform 2210is less than the inrush power 2110, the electrical components of theload would derate slower and the overall lifetime of the electricalcomponents may be extended.

FIG. 23A is an example of a typical AC power supply waveform 2300 wherepower is applied at activation time 2310 (also corresponding toactivation time 510 of FIGS. 5 and 7).

FIG. 23B is an example of gradual clipping of an AC power supplywaveform to achieve a soft start that reduces inrush. At activation time2310, power is applied for a first portion 2330 of a first AC cycle. Athe second half of the first AC cycle, power is applied for a secondlarger portion 2340 of the AC waveform In a first half of a second ACcycle, power is applied for a third larger portion 2350. In a secondhalf of a second AC cycle, power is applied for a fourth larger portion2360. In a first portion of a third AC cycle, power is applied for afifth larger portion 2370. Thereafter, full power may be applied to theload.

In general, the gradual application of power achieves the soft-startsystem. Although only five increasing applications of power are show,the soft start feature may provide for gradual application of power overmany AC cycles. Moreover, the application of power may be on the highside or the low side, or both (as shown), of the AC cycle. Thus, thesoft start system as shown herein is an example of a soft start systemand is not limiting.

Relating the gradual application of power from a small portion of fullpower to full power relates back to the stabilization period 820 shownin FIGS. 7 and 8. For example, the application of power at activationtime 2310 may also relate with activation time 510 of FIGS. 5-8.Moreover, the various times of partial application of power (e.g., firstportion 2330, second larger portion 2340, third larger portion 2350,fourth larger portion 2360, and fifth larger portion 2370) may beperformed in the window of time shown in FIGS. 7 and 8 during the timerperiod defined by activation time 510 and stabilization end time 830.Application of full power may be before or at stabilization end time 830(see FIGS. 7 and 8). Moreover, full power may be applied during samplingwindow 840 to avoid varying current consumption while sampling powerdemand.

The present invention has been particularly shown and described withreference to the foregoing embodiments, which are merely illustrative ofthe best modes for carrying out the invention. It should be understoodby those skilled in the art that various alternatives to the embodimentsof the invention described herein may be employed in practicing theinvention without departing from the spirit and scope of the inventionas defined in the following claims. The embodiments should be understoodto include all novel and non-obvious combinations of elements describedherein, and claims may be presented in this or a later application toany novel and non-obvious combination of these elements. Moreover, theforegoing embodiments are illustrative, and no single feature or elementis essential to all possible combinations that may be claimed in this ora later application.

With regard to the processes, methods, heuristics, etc. describedherein, it should be understood that although the steps of suchprocesses, etc. have been described as occurring according to a certainordered sequence, such processes could be practiced with the describedsteps performed in an order other than the order described herein. Itfurther should be understood that certain steps could be performedsimultaneously, that other steps could be added, or that certain stepsdescribed herein could be omitted. In other words, the descriptions ofprocesses described herein are provided for illustrating certainembodiments and should in no way be construed to limit the claimedinvention.

Accordingly, it is to be understood that the above description isintended to be illustrative and not restrictive. Many embodiments andapplications other than the examples provided would be apparent to thoseof skill in the art upon reading the above description. The scope of theinvention should be determined, not with reference to the abovedescription, but should instead be determined with reference to theappended claims, along with the full scope of equivalents to which suchclaims are entitled. It is anticipated and intended that futuredevelopments will occur in the arts discussed herein, and that thedisclosed systems and methods will be incorporated into such futureembodiments. In sum, it should be understood that the invention iscapable of modification and variation and is limited only by thefollowing claims.

All terms used in the claims are intended to be given their broadestreasonable constructions and their ordinary meanings as understood bythose skilled in the art unless an explicit indication to the contraryis made herein. In particular, use of the singular articles such as “a,”“the,” “said,” etc. should be read to recite one or more of theindicated elements unless a claim recites an explicit limitation to thecontrary.

1. A system comprising: a master power saving device configured forconnection with a master load, said master power saving deviceconfigured to determine when said master load is in an operatingcondition and a non-operating condition based on said load demand of themaster load, and wherein said master power saving device providesnon-continuous power to said master load when said master load is in anon-operating condition; and a slave power saving device configured forconnection with a slave load, said slave power saving device configuredto receive a signal from said master power saving device to turn offsaid slave load.
 2. The system of claim 1, wherein said master powersaving device communicates with said slave power saving device usingpower line communication.
 3. The system of claim 1, wherein said masterpower saving device communicates with said slave power saving deviceusing wireless communication.
 4. The system of claim 1, wherein saidslave power saving device is further configured to receive a signal fromsaid master power saving device to turn on said slave load.
 5. Thesystem of claim 1, wherein said slave power saving device is furtherconfigured to determine when said slave load is in an operatingcondition and a non-operating condition, and wherein said slave powersaving device provides non-continuous power to said slave load when saidslave load is in a non-operating condition.
 6. The system of claim 1,wherein said load demand comprises at least one of electrical currentand power.
 7. The system of claim 1, wherein said slave power savingdevice is paired with said master power saving device to receive saidsignal.
 8. The system of claim 1, further comprising a plurality ofslave power saving devices configured to receive said signal from saidmaster power saving device.
 9. A system comprising: a sensor configuredto determine whether a human is in the area of the sensor, said sensorproviding a signal when a human is determined to be in the area; and apower saving device configured to receive said signal, said power savingdevice configured for connection with a load, said power saving deviceconfigured to determine when said load is in an operating condition anda non-operating condition based on a load demand, and wherein said powersaving device provides non-continuous power to said load when said loadis in a non-operating condition, and wherein said power saving deviceemploys a first power saving strategy when said signal is received and asecond power saving strategy when said signal is not received.
 10. Thesystem of claim 9, wherein said sensor comprises a motion sensor. 11.The system of claim 9, wherein said first power saving strategycomprises pulsing power to said load.
 12. The system of claim 9, whereinsaid second power saving strategy comprises removing power from saidload.
 13. The system of claim 9, wherein said first power savingstrategy comprises pulsing power having a first period to said load. 14.The system of claim 13, wherein said second power saving strategycomprises pulsing power having a second period to said load.
 15. Thesystem of claim 14, wherein said second period is longer than said firstperiod.
 16. A method for controlling an electrical load: providing powerto a load for a predetermined time; measuring a load demand; determiningwhether the load is turned on by said measured load demand; andrepeating said steps of providing, measuring, and determining, whereinwith each repetition said predetermined time is extended to a longerpredetermined time until said load is determined to be on.
 17. Themethod of claim 16, wherein said step of determining said load demandfurther comprises: comparing said load demand with a predeterminedthreshold.
 18. The method of claim 16, further comprising: removingpower to said load for a second predetermined time after the step ofmeasuring.
 19. The method of claim 18, further comprising: instructingsaid load to turn on during said providing and determining.
 20. Themethod of claim 19, further comprising: storing said predetermined timeused when the load is determined to be on.